The present invention relates to a control device for the automatic alignment of a laser beam. It more particularly applies to the field of utilizing the energy of a laser beam, in which the beam must be directed in a preferred direction. The invention more particularly applies to machining by laser, which requires the directing of a beam from a power laser onto the orifice of a nozzle by means of focusing optics.
The laser beams in question are those whose transverse energy distribution substantially has a central symmetry. They are in particular substantially Gaussian laser beams from lasers emitting essentially in accordance with the fundamental mode TEM.sub.00.
Pyroelectric laser beam positioning of alignment detectors are known. Such detectors suffer from the disadvantage of not being able to readily withstand the high densities of high energy power, which limits their use to relatively low energy laser beams and prevents their use with power lasers.
Other laser beam alignment detectors are known, which can be used with power lasers and for this purpose has thermoelectric detection means fixed to thermally absorbent measuring surfaces acting as black bodies. These other detectors suffer from the disadvantage of having slow response times in proportion to the diffusion of heat in the absorbing surfaces. They also suffer from the disadvantage of having very large measuring surfaces absorbing a larg part of the energy of the incident laser beam, which is highly prejudicial when this beam is continuously used for machining, which requires a high energy density.